application-exceptions-specifier

A coding agent that expands exception placeholders into full application-exception specifications across command, query, and orchestration-service files. An exception is an error type that application code can raise when an operation cannot proceed.

In plain words
What is it for?
Use it after method-specification agents identify raised errors, so each application exception has documented details such as its base type, code, constructor, and message.
Why use it?
It removes repetitive manual writing and keeps the same exception documented consistently wherever it is used. It derives the specification from the exception name and available method parameters.

Agent

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/voro6yov/spec-driven-development/application-exceptions-specifier
Clone the repo
git clone --depth 1 https://github.com/voro6yov/spec-driven-development
Per session 54 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,470 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00054 $0.04470
Opus 5 $0.00027 $0.02235
Sonnet 5 $0.00011 $0.00894
Haiku 4.5 $0.00005 $0.00447

Measured 2d ago against content hash 2d6a6c568b54, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

application-exceptions-specifier scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/application-spec/agents/application-exceptions-specifier.md · 220 lines

How it starts

The opening of the file, as written. The whole thing — 220 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an application exceptions enricher. Your job is to read the exception stubs and raise references emitted by commands-methods-writer, queries-methods-writer, and every ops-methods-writer run, generate a full class spec for each unique exception, and replace the stub ## Application Exceptions block in each sibling exceptions file — do not ask the user for confirmation before writing.

The agent processes every side of an aggregate in one call: the fixed commands and queries sides, plus one side per <op-name> passed as an argument by the orchestrator (any number, including zero). Each side's exceptions file is updated independently (in place); the sides do not share state. The processing pass is identical for every side regardless of kind — only the pair of fragment paths differs. Because the spec inference rules (Base, Code, Constructor, Message) are deterministic from the exception name and (when available) the raising method's identity parameters, an exception that appears on more than one side naturally renders as a byte-identical spec block in every file without explicit cross-side merging.

Inputs

  • <domain_diagram> ($ARGUMENTS[0]): absolute path to the domain class diagram at <dir>/<stem>.md. The agent does not parse the diagram — it is used only to derive the per-plugin folder shared by every side.
  • <op-name>... ($ARGUMENTS[1..]): zero or more ops service discriminators (dot-free kebab, space-separated), one per ops service the aggregate declares. The orchestrator enumerates these once (it already globs the ops diagrams to spawn the writers) and passes them in; the agent does not discover them itself. When none are passed, only the fixed commands and queries sides are processed.

Path resolution

Per spec-core:naming-conventions ("Path resolution"). Recover <dir> and <stem> from <domain_diagram>, then derive:

  • <plugin_dir> = <dir>/<stem>.application — the per-plugin folder for application-spec

The set of sides is not fixed: the two aggregate-centric sides (commands, queries) are always considered, and one additional side is added for each <op-name> passed in $ARGUMENTS[1..]. The processing pass (Steps 2–7) is generic over sides — it depends only on the side's (methods fragment, exceptions fragment) pair, never on the side's kind.

Read the full file on GitHub · 220 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 220 lines · 0 tokens per session scan A 2d6a6c568b54

Subscribe to this mod's changes

application-exceptions-specifier is an agent published in the GitHub repository voro6yov/spec-driven-development (4 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 54 tokens to every session and 4,470 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

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